Thermoplastics are compositions which can be molded or otherwise shaped and reprocessed at temperatures above their melting or softening points. Thermoplastic elastomers (elastoplastics) are materials which exhibit both thermoplastic and elastomeric properties, i.e., the materials can be processed as thermoplastics but they have physical properties like elastomers. Shaped articles may be formed from thermoplastic elastomers by extrusion, injection molding or compression molding without the time-consuming cure step required with conventional vulcanizates. Elimination of the time required to effect vulcanization provides significant manufacturing advantages. Further, thermoplastic elastomers can be reprocessed without the need for reclaiming, and, in addition, many thermoplastics can be thermally welded.
Moldable thermoplastic compositions of nylon and thermoplastic urethane rubber containing high proportions of nylon and exhibiting high impact strength are known but such compositions are rigid materials of high stiffness and low elongation (Epstein, U.S. Pat. No. 4,174,358). Moldable elastoplastic compositions of nylon and cured high unsaturation diene rubbers containing high proportions of rubber are known (A. Y. Coran and R. Patel, U.S. Pat. No. 4,173,556).